Fullerenes have recently been investigated for novel synthetic approaches and new uses. These hydrocarbon compounds possess a form containing a network of pentagons and hexagons. The fullerenes have been found to have several different molecular weights, depending on how many carbon atoms are in the cage. One particular form of fullerene is the C.sub.60 molecule which has the highest possible symmetry (icosahedral) and assumes the shape of a soccer ball.
Tribology is the science of friction, wear, and lubrication. Solid lubricants are of significant commercial importance, but require certain properties. It is desired to have a solid lubricant which has low surface energy, high chemical stability, weak intermolecular bonding, good transfer film forming capability and high load bearing capacity. Conventional solid lubricants such as MoS.sub.2, graphite, and polytetrafluoroethylene (PTFE) have weak interlayer bonding which facilitate transfer of said materials to the mating surface. Such transfer films are partially responsible for low friction and wear. Graphite exhibits low friction in the presence of moisture and rather high friction in vacuum with an operating temperature limit of about 430.degree. C. MoS.sub.2 provides low friction at low humidity and in vacuum with an operating temperature limit of about 315 .degree. C. PTFE is a soft polymer that exhibits low friction and rather high wear and its use is limited only to light loads and moderate temperature (about 200.degree. C.) applications. Ajie, et at., J. Phys. Chem., 1990, volume 94, pp. 8630-8633, and Haufler et at., Mat. Res. Soc. Symp. Proc. 1991, volume 206, pp. 627-637, teach a method of providing fullerenes by arc evaporation of pure graphite in helium atmosphere.
PCT patent application WO92/20622, published Nov. 26, 1992 for Howard, et at., teaches a method for synthesizing fullerenes in flames.
Fullerene soot containing C.sub.60, C.sub.70, and other higher fullerene molecules have been produced by other researchers using the following processes in addition to arc evaporation of pure graphite in helium atmosphere. Evaporation of isostatically pressed pure graphite, pyrolytic graphite, and amorphous carbon by heating inductively at about 2700.degree. C. temperature and at a helium atmosphere of 150 Pa is reported by Peters and Jansen, Angew. Chem. Int. Ed. Engl. 1992, volume 31, No.2, pp. 223-224.
Yoshie et at., Appl. Phys. Lett. Dec. 7, 1992, volume 61, pp. 2782-2783, teaches the evaporation of carbon black, benzene, acetylene in a hybrid plasma that comprises a rf plasma and a dc arc jet in vacuum to atmospheric pressure to produce fullerenes.
Howard et at., Nature, Jul. 11, 1991, volume 352, pp. 139-141, teaches the formation of fullerenes from hydrocarbon combustion, in which the ratio of C.sub.60 and C.sub.70 and their yield depend on the temperature, pressure, carbon/oxygen ratio and the residence time in the flame.
Scrivens, et al., J. Am. Chem. Soc. 1992, volume 114, pp. 7917-7919, teaches a method for producing and purifying C.sub.60 fullerenes.
However, not all prior art fullerene materials are good for tribology. Thus, a need exists for new materials that can provide low friction and low wear over a wide range of operating conditions. Such materials should ideally be able to impart such tribological properties alone and/or as an additive to improve the properties and performance of conventional liquid oil base lubricants, greases, organic polymers, and other organic and inorganic materials.